Draft:Fragility function

In structural engineering, a fragility function expresses the occurrence or exceedance probability of an undesirable outcome to the degree of one or more measures of environmental excitation. It is usually conditioned on a clearly defined asset class. For example, a fragility function can express the probability that a window of a given size and with clearly defined materials and dimensions will at least crack when it is subjected to varying degrees of peak transient interstory drift. The undesirable outcome is "window cracks." Here, "occurrence or exceedance" means that the window could crack (occurrence) or a more severe outcome could happen (exceedance), such as glass falling out. In this example, the environmental excitation is peak transient interstory drift.